The Scope of Biology

The Scope of Biology

Classifying Life

• Classification - organizing similar species into larger groups

DNA and Genes

The Three Domains of Life

Ecosystems

• Domain: The broadest category for classifying life forms
• Archaea and Bacteria are both unicellular and very tiny organisms that usually lack nuclei
• Cells without a nucleus are called prokaryotes

• The community of living things in an area along with the non living features of the environment that support the living community
• Example: Woodland area with trees ,plants, animals, and microscopic organisms
• Nonliving Features: Sunlight, Water, Air, Soil
• All ecosystems combined make up the biosphere

• DNA is the chemical responsible for inheritance and the units of inheritance are genes
• Parents pass their genes to their offspring
• Genes contain the instructions that direct all the molecules of the cell to make more molecules necessary for function

Biosphere

The Three Domains of Life Continued

• Eukaryotes are cells with a nucleus that hold their genetic information
• Eukarya includes four kingdoms: protists, fungi, plants, and animals
• Most organisms in this domain are multicellular meaning the are made of many cells, not just one an example is the human body

• Consists of all parts of the planet inhabited by living things
• Example: Earth
• Includes most regions of land; bodies of water such as oceans, lakes, and rivers and the atmosphere up to a height of several kilometers

Cells

• Life's basic units of structure and function
• All organisms are made up of one or more cells
• Inside the cell are several smaller structures including the nucleus which controls the activities of the cell
• It would take approximately 700 cells to make a straight line across a penny

Organisms

• Individual living things
• Example: Squirrel
• Interactions between the organisms create a dynamic environment
• Different types of organisms are called species, they are distinct forms of life

Scientific Inquiry

Biology and Society

• Inquiry involves asking questions about nature and using observations/experiments to find the answers to these questions

Biological Systems

• System: When a combination of parts form a more complex organization
• All parts need to interact in order for the system to work
• Example: A bike can't work if all the parts are just in the box they need to be put together
• Your body is a very complex system
• Ecosystems are also biological systems

• Every day biologists are discovering new findings in the fields of medicine and agriculture
• An example is were genetically modifying crops
• Treatments are being discovered for illnesses and diseases
• We are becoming more aware of environmental issues such as water and air pollution

Adaptation and Evolution

The Cellular Basis of Life

• Adaptation: an inherited trait that helps the organism to reproduce and survive in its environment
• Population: localized group of organisms belonging to a species
• Genes cause hereditary variation which makes it possible for a population to adapt to its environment
• Natural Selection: If a variation is helpful it allows for an individual to live longer and reproduce (environment "selecting" preferred traits)
• Evolution: a process of generation to generation change caused by natural selection

• All organisms are made of cells
• All cells are specified for certain functions in multicellular organisms
• Example: Muscle cells contract and allow you to move but your nerve cells control the movement
• Cells are organized into the following levels: tissue, organ, organ system, and organism

The Ten Themes of Life

Regulation

• The ability of an organism to regulate their internal conditions
• In the human body your brain is the thermostat that controls your body temperature
• Your brain signals your body to sweat which cools your body
• The ability of mammals and birds to regulate body temperature is homeostasis which allows them to regulate their body temperature even if the environment changes

Form and Function

• Form fits function
• Example: The bird wing has honeycomb-like structured bones which allows the organism to be light weight but still fly

Energy and Life

• All activities of life such as moving, growing and reproducing require organisms to perform work
• Work depends on a source of energy that in humans is obtained through the sugars and fats in food
• Energy flow can be traced through ecosystems: it first flows in as sunlight and later exits as heat
• Producers: produce the food upon which the entire ecosystem depends upon example: plants
• Consumers: animals and other organisms that eat the food made by producers
• Chemical energy is converted to other forms of energy which allows for the organism to carry out its life activities

Reproduction and Inheritance

Interaction with the Environment

• Genes are responsible for family resemblance
• When a cell divides it copies its DNA and passes it onto the two cells that it creates
• Fertilization is when a sperm cell and egg cell and their DNA fuse together to form a fertilized egg
• The fertilized egg later becomes a person

• Every organism is always interacting with its environment
• Example: Plant uses materials from its environment to carry out photosynthesis and animals later eat the plant as food
• Living requires a daily balance of "inputs" and "outputs"
• Each organism takes in what needs to survive and gets rid of waste which may be used by other organisms
• Organisms are constantly responding to changes in the environment